/*
 * Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.swing.colorchooser;

import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.text.ParseException;

import static java.util.Locale.ENGLISH;

import javax.swing.JFormattedTextField;
import javax.swing.JFormattedTextField.AbstractFormatter;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultFormatterFactory;
import javax.swing.text.DocumentFilter;

final class ValueFormatter extends AbstractFormatter implements FocusListener, Runnable {

  static void init(int length, boolean hex, JFormattedTextField text) {
    ValueFormatter formatter = new ValueFormatter(length, hex);
    text.setColumns(length);
    text.setFormatterFactory(new DefaultFormatterFactory(formatter));
    text.setHorizontalAlignment(SwingConstants.RIGHT);
    text.setMinimumSize(text.getPreferredSize());
    text.addFocusListener(formatter);
  }

  private final DocumentFilter filter = new DocumentFilter() {
    @Override
    public void remove(FilterBypass fb, int offset, int length) throws BadLocationException {
      if (isValid(fb.getDocument().getLength() - length)) {
        fb.remove(offset, length);
      }
    }

    @Override
    public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet set)
        throws BadLocationException {
      if (isValid(fb.getDocument().getLength() + text.length() - length) && isValid(text)) {
        fb.replace(offset, length, text.toUpperCase(ENGLISH), set);
      }
    }

    @Override
    public void insertString(FilterBypass fb, int offset, String text, AttributeSet set)
        throws BadLocationException {
      if (isValid(fb.getDocument().getLength() + text.length()) && isValid(text)) {
        fb.insertString(offset, text.toUpperCase(ENGLISH), set);
      }
    }
  };

  private final int length;
  private final int radix;

  private JFormattedTextField text;

  ValueFormatter(int length, boolean hex) {
    this.length = length;
    this.radix = hex ? 16 : 10;
  }

  @Override
  public Object stringToValue(String text) throws ParseException {
    try {
      return Integer.valueOf(text, this.radix);
    } catch (NumberFormatException nfe) {
      ParseException pe = new ParseException("illegal format", 0);
      pe.initCause(nfe);
      throw pe;
    }
  }

  @Override
  public String valueToString(Object object) throws ParseException {
    if (object instanceof Integer) {
      if (this.radix == 10) {
        return object.toString();
      }
      int value = (Integer) object;
      int index = this.length;
      char[] array = new char[index];
      while (0 < index--) {
        array[index] = Character.forDigit(value & 0x0F, this.radix);
        value >>= 4;
      }
      return new String(array).toUpperCase(ENGLISH);
    }
    throw new ParseException("illegal object", 0);
  }

  @Override
  protected DocumentFilter getDocumentFilter() {
    return this.filter;
  }

  public void focusGained(FocusEvent event) {
    Object source = event.getSource();
    if (source instanceof JFormattedTextField) {
      this.text = (JFormattedTextField) source;
      SwingUtilities.invokeLater(this);
    }
  }

  public void focusLost(FocusEvent event) {
  }

  public void run() {
    if (this.text != null) {
      this.text.selectAll();
    }
  }

  private boolean isValid(int length) {
    return (0 <= length) && (length <= this.length);
  }

  private boolean isValid(String text) {
    int length = text.length();
    for (int i = 0; i < length; i++) {
      char ch = text.charAt(i);
      if (Character.digit(ch, this.radix) < 0) {
        return false;
      }
    }
    return true;
  }
}
